Genotyping for Plasmodium spp.: Diagnosis and Monitoring of Antimalarial Drug Resistance

Malaria is one the world’s most widespread lethal diseases. Plasmodium falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi induce human pathology. These species could be differentially diagnosed using the genotyping of cytochrome b, Pfdhfr and RNA 18S. The persistence of P. falciparum, the most lethal parasite, is mainly due to antimalarial drug resistance. Indeed, a few years after the start of the ambitious malaria eradication program in 1960, chloroquine resistance emerged in Asia and spread widely in all the endemic areas. It was associated with genotypes in P. falciparum chloroquine resistance transporter (CVIET, SVMNT, CVMNT, CVIDT, SVIET and CVMET). The use of new drugs such as sulfadoxine-pyrimethamine (SP) leads quickly to SP-resistant parasites associated with genotypes on P. falciparum DiHydroFolate reductase (I51-R59-N108-I164) and P. falciparum DiHydroPteroate synthetase (436-437-580-613). Recently, the delay of parasite clearance has been described with artemisinine (the most efficacious antimalarial drug). This resistance was associated with the K13 propeller genotype. Since malaria species and antimalarial drug resistance markers could be characterized using nucleic acid sequences, genotyping is needed for malarial monitoring of species distribution and antimalarial drug resistance

Y a-t-il des politiques migratoires nationales ? De quelques leçons des années 1920

Depuis une vingtaine d'années, l'historiographie prête une attention de plus en plus fine au rôle des États dans le contrôle des migrations internationales, entendu dans ses aspects à la fois politiques et économiques. De la reconstitution du cadre légal des politiques publiques, à la sociographie de leur mise en oeuvre quotidienne par les fonctionnaires en contact avec les migrants, émergent des aspects toujours plus nombreux de la " tyrannie du national "2. On peut cependant, en croisant les approches portant sur plusieurs pays d'émigration et d'immigration, et en élargissant l'échelle d'observation à un espace transnational, mettre l'accent sur des aspects complémentaires, dont la prise en considération est indispensable à la compréhension des dynamiques et des tensions de ce que l'on a parfois désigné comme une " première mondialisation "3 (...)

Artifacts associated with the measurement of oxidized DNA bases.

In this paper we review recent aspects of the measurement of oxidized DNA bases, currently a matter of debate. There has long been an interest in the determination of the level of oxidized bases in cellular DNA under both normal and oxidative stress conditions. In this respect, the situation is confusing because variations that may be as large as two orders of magnitude have been reported for the yield of the formation of 8-oxo-7,8-dihydroguanine (8-oxoGua) in similar DNA samples. However, recent findings clearly show that application of several assays like gas chromatography-mass spectrometry (GC-MS) and -32P--postlabeling may lead to a significant overestimation of the level of oxidized bases in cellular DNA. In particular, the silylation step, which is required to make the samples volatile for the GC-MS analysis, has been shown to induce oxidation of normal bases at the level of about one oxidized base per 10(4) normal bases. This has been found to be a general process that applies in particular to 8-oxoGua, 8-oxo-7, 8-dihydroadenine,5-hydroxycytosine, 5-(hydroxymethyl)uracil, and 5-formyluracil. Interestingly, prepurification of the oxidized bases from DNA hydrolysate prior to the derivatization reaction prevents artefactual oxidation. Under these conditions, the level of oxidized bases measured by GC-MS is similar to that obtained by HPLC associated with electrochemical detection (HPLC-EC). It should be added that the level of 8-oxo-7,8-dihydro-2;-deoxyguanosine in control cellular DNA has been found to be about fivefold lower than in earlier HPLC-EC measurements by using appropriate conditions of extraction and enzymatic digestion of DNA. Similar conclusions were reached by measuring formamidopyrimidine-DNA glycosylase sensitive sites as revealed by the single cell gel electrophoresis (comet) assay

Y a-t-il des politiques migratoires nationales ? De quelques leçons des années 1920

Depuis une vingtaine d’années, l’historiographie prête une attention de plus en plus fine au rôle des États dans le contrôle des migrations internationales, entendu dans ses aspects à la fois politiques et économiques. De la reconstitution du cadre légal des politiques publiques, à la sociographie de leur mise en oeuvre quotidienne par les fonctionnaires en contact avec les migrants, émergent des aspects toujours plus nombreux de la « tyrannie du national »2. On peut cependant, en croisant les approches portant sur plusieurs pays d’émigration et d’immigration, et en élargissant l’échelle d’observation à un espace transnational, mettre l’accent sur des aspects complémentaires, dont la prise en considération est indispensable à la compréhension des dynamiques et des tensions de ce que l’on a parfois désigné comme une « première mondialisation »3 (...)

Quantitative analysis of UV photolesions suggests that cyclobutane pyrimidine dimers produced in mouse skin by UVB are more mutagenic than those produced by UVC

International audienc

UV-Induced Structural Changes of Model DNA Helices Probed by Optical Spectroscopy

International audienceChemical alterations of DNA, if not repaired, may lead to carcinogenic mutations. Structural modifications of the helix around the lesion enable its recognition by repair enzymes. We have used absorption spectroscopy and mass spectrometry to detect structural changes provoked by cyclobutane thymine dimers, the major lesion induced by UV radiation. We found that formation of a cyclobutane dimer in the model duplex (dA)20 · (dT)20 destroys base stacking on the adenine strand. The physical background of this novel approach is the existence of charge-transfer states among neighboring bases, whose contribution to the hypochromism of the helix disappears following destacking

Photosensitized [2 + 2] cycloaddition of N-acetylated cytosine affords stereoselective formation of cyclobutane pyrimidine dimer

Photocycloaddition between two adjacent bases in DNA produces a cyclobutane pyrimidine dimer (CPD), which is one of the major UV-induced DNA lesions, with either the cis-syn or trans-syn structure. In this study, we investigated the photosensitized intramolecular cycloaddition of partially-protected thymidylyl-(3′→5′)-N4-acetyl-2′-deoxy-5-methylcytidine, to clarify the effect of the base modification on the cycloaddition reaction. The reaction resulted in the stereoselective formation of the trans-syn CPD, followed by hydrolysis of the acetylamino group. The same result was obtained for the photocycloaddition of thymidylyl-(3′→5′)-N4-acetyl-2′-deoxycytidine, whereas both the cis-syn and trans-syn CPDs were formed from thymidylyl-(3′→5′)-thymidine. Kinetic analyses revealed that the activation energy of the acid-catalyzed hydrolysis is comparable to that reported for the thymine-cytosine CPD. These findings provided a new strategy for the synthesis of oligonucleotides containing the trans-syn CPD. Using the synthesized oligonucleotide, translesion synthesis by human DNA polymerase η was analyzed

Étude de l'impact des réservoirs sur la qualité de l'eau distribuée

Présentation des réservoirs d'eau potable de la Ville de Montréal -- Types de réservoirs -- Principales causes de la dégradation de la qualité de l'eau dans les réservoirs fermés -- Matériels et méthodes -- Description des réservoirs étudiés -- Échantillonnage périodique à l'entrée et à la sortie des réservoirs -- Description d'un échantillonnage ponctuel à l'intérieur des réservoirs -- Influence des conditions hydrauliques sur la qualité de l'eau dans les réservoirs -- Évolution de la qualité de l'eau à l'entrée et à la sortie des réservoirs -- Résultats des campagnes d'échantillonnage à l'intérieur des réservoirs -- Deuxième série de campagne d'échantillonnage dans les réservoirs -- Campagnes d'échantillonnage dans le réservoir McTavish -- Évolution de la qualité de l'eau dans les réservoirs McTavish, Côte-des-Neiges et Sommet durant la deuxième campagne -- Développement et application de la technique d'hybridation in-situ (fish) pour la détection des bactéries coliformes dans l'eau potable

Rapid multi-residue method for the determination of pesticide residues in human serum

Exposure to pesticides can represent a potential risk to humans. Agricultural workers are at risk of chronic toxicity. Hence, the evaluation of pesticide residues in their blood gives an indication about the extent of exposure and help in assessing adverse health effects. The aim of our study was to develop analytical method for the simultaneous determination of some residues of pesticides using gas chromatography-mass spectrometry (GC-MS). This method involves a liquid-liquid extraction procedure. Pesticide residues were separated and detected using GC-MS, and acquisition was performed in the sellected ion monitoring (SIM) mode. For most of the pesticides, average recoveries ranged between 65 and 101% at three different fortification levels. The linearity of the method was satisfactory in the range of 5 to 50 ng/ml, with a correlation coefficient between 0.998 and 0.999, depending on the analyte. The estimated limit of detection and limit of quantification ranged from 2 to 5 ng/ml and from 5 to 10 ng/ml, respectively. The method precision and accuracy were found to be satisfactory at three concentration levels. The variation coefficients of intra-day and inter-day precision ranged from 0.4 to 14% and from 2.5 to 15%, respectively for most studied pesticides.Keywords: Analytical methods, human serum, GC-MS, pesticide residues, validatio

Research on Treating Demineralized Enamel with Different Remineralizing Agents before Bonding Orthodontic Brackets

Many orthodontic clinics have problems with patients who have dental demineralization. This study aimed to evaluate “the shear bond strength (SBS)” of braces after being bonded to demineralized teeth treated with herbal materials. Our study samples were divided into five groups. The first group was left with no treatment. The surfaces of the second, third, and fourth groups were first treated with a demineralizing solution. The second group was left after being demineralized without any subsequent treatment; the third group was treated with rosemary oil; the fourth was treated with ginger–honey. Casein phosphopeptide–amorphous calcium phosphate with fluoride paste (CPP–ACPF) was applied to the fifth group. A universal testing machine evaluated the SBS. A stereomicroscope was used to determine the adhesive remnant index (ARI). The enamel surface changes were observed using surface microhardness (SMH) testing, scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) to determine the element percentages. Our data revealed that the values of both SBS and SMH were significantly (p < 0.05) increased after remineralization. Rosemary and ginger–honey significantly enhanced the SBS and SMH of the demineralized teeth